Due to the necessity of mounting boots on a joint casing by way of a binder element, a problem exists with respect to the fitting of the boot on the joint casing due to the stress exerted from the binder element and a flowing into spaces underneath the binder element, thereby loosening the connection with each other. In order to solve that problem, U.S. Pat. No. 5,094,894 proposes a boot with at least one collar region, comprising, on its outside, an annular groove with a rectangular or trapezoidal cross-section for a tensioning element, the annular groove being provided with a substantially flat bottom part resting against the tensioning element and is wider than an internal annular bead. The collar region, within the flat annular groove in the region of the internal annular bead, comprises at least one recess-like annular gap with a rectangular or trapezoidal cross-section whose cross-sectional depth is greater than its width. Further, on the inner surface of the collar region, resting against the joint casing, two annular beads are assigned to the two recess-like annular gaps shown in the Fig. of U.S. Pat. No. 5,094,894. However, the problem of the embodiment disclosed in U.S. Pat. No. 5,094,894 is that it may not be fixed in a defined axial position in an annular groove of a joint casing. The boot in accordance with U.S. Pat. No. 5,094,894 will show a high flexibility in the axial direction with respect to the fixing of the same by a binder element in an annular groove of a joint casing, whereby the flexibility will cause deformations during tensioning. Further, the pressure forces exerted by the binder element will flow in an uncontrolled way into the material of a boot in the binder seat region giving rise for sealing problems.
Thus, what is needed is a boot having increased sealing and fixing properties.